Tensiometer control system



s. P.:LESSMANN 25,249,339

TENSIOMETERY CONTROL SYSTEM Filed Sept. 8, 1938 4 Sheets-Sheet 1Comra/Av' WITNESSES: iNVENTOR @49 WW GeflMrd Less/72mm.

y 1941- s. BLESSMANN V 2,249,839

TENSIOMETER CONTROL SYSTEM Filed Sept. a, 1938 4 Sheets-Sheet 2 ATTORNEYYZ 1941. 5. P. LESSMANN 2,249,839

TENSIOMETER CONTROL SYSTEM Filed Sept. 8, 1938 4 Sheets-Sheet 3WITNESSES: INVENTOR 9& W Gerhard FZessma/7/z fa 0&7

v ATTORN I July 22, 1941.. v G. P.'LESSMANN 9 TENSIOMETER CONTROL SYSTEMFiled Sept. 8, 1938 4 Sheets-Sheet 4 Patented July 22, 1941 TENsIoME'rEnCONTROL SYSTEM Gerhard P. Lessmann, Forest*Hills,1Pa., assignor toWestinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,a-corporation of Pennsylvania Application September 8, 1938, Serial'No.228,941

16 Claims.

My invention relates, generally, to strip tensioning devices and, moreparticularly, to means for controlling the operation of tensiometerdevices for subjecting a strip of material to-tension' as itpasses'between two work devices.

In the manufacture of sheet steel, it has been found efficient andeconomical to subject the steel to tension as it passes in the form of astrip, through a tandem rolling mill. A very successful form oftensioning device for this purpose is disclosed in my copendingapplication Serial No. 133,419, filed March 2'7, 1937, now Patent No.2,189,609, to which reference is made for a complete description of itsconstruction and operation; The device disclosed by the above-identifiedapplication comprises generally a bell crank upon one arm of which thereis mounted an idling roller which bears against the strip as it passesbetween adjacent roll stands of a tandem mill deflecting the strip fromthe normal pass line and thus tensioning the strip. The tensioning forceis applied to the bellcrank by means of a pressure fluid operatedpiston, the tension being controlled by controlling the fluid pressureacting'on the piston and regulating the speed-of the rolls of theadjacent roll stands to limit the amount of deflection of the strip bythe idling roller.

In some mills it is desirable that such tensioning devicesmay be capableof producing an extremely wide range of strip tensions, since, for agiven: strip thickness, the total strip tension will provideanautomatically controlled tensiom'ng device for a strip rolling mill.

Another object of the invention is to provide a control system for astrip tensioning device which shall function to provide a wide range oftensions.

A' further object of the invention is to provide a control system for astrip tensioning device which shall function to provide a wide range ofmanually selectable tensions and which shall operat'e toapply or releasethe selected tension in response to predetermined mill conditions.

Another object of the invention is to provide asimple and efficientstrip tensioning device for a strip rolling mill which shall beinexpensive to manufacture, install and maintain.

These and other objects and advantages of my invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings, in which like reference characters-designate likeelements and in which:

Figure 1 is a diagrammatic illustration of a portion of a strip rollingmill and a strip tensioning device and control therefor embodying theprincipal features'of my invention,

Figs: 2 through 8 are diagrammatic illustrations of variouscontrolsystems for strip tensioning devices embodying the principalfeatures of my invention.

In it's general aspects, apreferredembodiment ofmy invention,showndiagrammatically in Fig. 1, comprises a tensioning device it]actuable by pressure fluid operated pistons l2 and !4-, piston l4-having a larger diameter than piston E2, to apply a transverse force tothe strip H3 as it passes between adjacent reducing roll stands 18 and2ll, thus tensioning the strip. The tension on the strip depends uponthe fluid pressure on the operating pistonsand is maintained at apredetermined adjustable amo'unt'by a fluid pressure regulating valve 22which is disposed between a high pressure fluid-reservoir as shown andthe operating pistons. This general arrangement of pressure fluidoperated strip tensioning device is' described indetail in my abovereferred to copending application to which reference is made for a moredetailed description of its struc- V ture and operation.

The tensioningdevice to is normally held in an inoperative position, asshown in Fig. 1, by means of a biasing spring 24 which may be compressedand-movedout of engagement with the tensioning device by a fluidpressure operated piston 26s An electromagnetically operated valvesystem 28 selectively causes either piston- 12 or piston M, dependingupon the desired strip tension,

to actuate the tensioning device and withdraws is applied to theoperating piston continuously, the biasing spring 24 normally overcomingthe force of the operating piston. In this embodiment the tensioningdevice is operated upon contraction of the spring 24 by the piston 26.

The embodiment shown in Fig. 4. is generally similar to that of Fig. 2with the two pistons l2 and I4 operated together.

Another embodiment of the invention is shown in Fig. 5. This systemoperates essentially the same as that shown in Fig. 3 with the twopistons l2 and I4 operating simultaneously.

The system of Fig. 6 provides selective opera tion of either or both ofpistons l2 and I4, differing from the system of Fig. 1 in that both ofthe pistons may be operated simultaneously.

A control system by which the two pistons of the system shown in Fig.may be operated selectively is shown in Fig. 7.

The control system of Fig. 8 differs from that of Fig. 7 in that the twooperating pistons may be selectively operated separately orsimultaneously.

In each of these control systems the actuation of the tensioning deviceis under the control of a load responsive relay 30 which initiates theoperation of the control valve system in response to the load on theroll stand preceding the tensioning device, so that the tensioningdevice may be in operation when the leading end of the strip bridges theroll stands adjacent the tensioning device.

Referring to the drawings for a more detailed description of myinvention, in Fig. l, the tensioning device 10 comprises a bell crank 32pivot- .ally mounted upon a support 34. The bell crank tion shown in thedrawings with the idling roller '33 below the normal pass line betweenthe roll stands l8 and 20.

The plate 43 is connected by a stem 48 to the piston 26 which operatesin the cylinder 50 under fluid pressure to retract the plate 46 againstthe tension of the spring 24 to thus remove the retracting bias from thebell crank 32.

The arm 49 of the bell crank 32 is connected by means of a rod 52 withthe pistons I2 and [4 which are operated by fluid pressure in thecylinders 54 and 53, respectively. The actuation of the arm 40 by apredetermined fluid pressure in the cylinder 54 after the spring 24 hasbeen retracted will force the arm 40 upward to rotate the bell crank 32in a clockwise direction and thus cause the idling tension roller 38 toengage and deflect the strip 16 upward from its normal pass line andthereby subject it to tension. In the preferred embodiment of myinvention, the normal operating position of the bell crank 32 will besuch that the arm 40 will be substantially horizontal or parallel to thenormal pass line between the roll stands l8 and 20 and the arm .36 willbe positioned at an angle of substantially 51 from the arm 43. With thispositioning of the arms 33 and 44, a substantially constant tension willbe maintained in the strip l6 within a predetermined range of deflectionof the strip l6 while a constant pressure is applied to the .pistonwhich actuates the arm 40. The details of thedimensions and the relativepositioning of the arms 36 and 40 are fully discussed in myabove-referred to patent.

Thus, with a predetermined pressure range available through theadjustment of the valve 22, a predetermined range of tensions may beapplied to the strip l6 by applying the range of pressures madeavailable by the pressure regulating valve 22 to the piston 12. If ahigher strip tension is desired, the predetermined range of fluidpressures made available by the pressure regulating valve 22 may beapplied to the piston I4 and the piston 14 being larger than piston 2, agreater force will be applied to the arm 43 for a given pressure onpiston I4 than on piston l2. An electromagnetic valve system 28 isprovided for selectively actuating the pistons l2 or [4 as desired.

The control for the piston l2 comprises an electromagnetically operatedvalve 58 which is connected by conduits 60 to a regulated pressurereservoir in which a predetermined pressure is maintained by thepressure regulating valve 22. The valve 58 is connected by a conduit 62to the cylinder 54. The cylinder 54 is connected to an electromagneticvalve 64 by means of a conduit 66 and the valve 64 is, in turn,connected by a conduit 68 to the cylinder 50. An electromagneticoperating releasevalve 10 has one side connected by a conduit 12 to thecylinder 53 and its other side is open to the atmosphere. A conduit 14connects a release valve 16 with the conduit 96. The release valve 16has one side open to the atmosphere.

In a similar manner an electromagnetically operated control valve 18 isconnected between the cylinder 56 and the regulated pressure reservoirby means of conduits 83 and 82. A control valve 84 is connected betweenthe cylinder 56 and the conduit 68 by means of conduits 86 and 88 and aconduit 92 connects one side of a release valve 33 with the conduit 86,the release valve 96 having its other side open to the atmosphere.

An electrical control system for the electromagnetic valves is providedand is made responsive to the potential drop across the interpolewinding 94 of the drive motor 35 of the roll stand [8. A selector switch96 is provided to select those parts of the valve control system whichwill cause piston [2 or l4 to be energized by fluid pressure, asdesired. The selector switch 98 comprises a movable contact element 91which, when moved in the left-hand direction, will engage fixed contactelements 98 and I00, and a second movable contact element I02 which,when moved in the right-hand direction, will engage contact elements I03and IE3. When it is desired to operate the tensioning device I0 by meansof fluid pressure applied to piston l2, the selector switch 96 ismanually actuated in the left-hand direction and then when the strip isfed through the mill and is engaged by the rolls of the roll stand [8,the increase in the load on the drive motor will energize the relay 30because of the increase in potential drop across the interpole winding94, and will close a circuit for the control valves 58, B4, 10 and 73which extend from one side X of a suitable source of electric current,indicated by conductors XY, through the conductors I04 and Hit, thecontact element '18 of relay 30, the conductor ill], the winding ofvalve 10, the con ductor H2, the contact element 91, the conductor I 14,the operating winding of valve 64, the conductor I [6, the operatingwinding of valve '16 the conductor H8, the operating winding of valveSB-and-the-condu'ctor I=2II-to the other power conductor Y. a

A similar controlcircuit is provided for the control valves I8; 84; 90and III which control the operation of the piston I4. This circuitextends fromthe conductor X through the conductors I64 and. "16, contactelement Hi8, conductor Hll', the operating windingof valve 13', theconductor- H2, contact element I92, the conductor I2 2, the operatingwinding 'oi' valve 84, the conductor I 24; the operating winding ofvalve 90, the-conductor I26, the operating winding of valve I'Gandconductors I28 and I20 to conduc'tor'Y'. I

The drive motor I30 for the rolls of' the roll stand 20 may be manuallycontrolled as indicated to maintain a predetermined amount of slack inthe strip I between the roll stand I8 and g sothat the deflection of thestrip It by the tensioning device It will be maintained withinpredetermined-limits or a suitable regulating device may be provided forthe motor I3l to control its speed in accordance with the amount ofdeflection of the strip I6 by the tensioning device II], as explained indetail in my hereinbefore referred to copending application.

In the operation of the system of Fig, 1 when a strip of such size orsuch characteristics as will require only the strip tension available byactuation of the'tensioning r011 38 by the piston I2 is to be rolled,the selector switch 96 is actuated' manually to move th contact elementso into engagement with the contact elements 98 and Iflfi. When thestrip as it is fed through the mill is'engaged by the rolls of rollstand It, the relay 3!) will be energized as hereinbefore describedmoving its contact elements I63 to closed circuit position. This willenergiz the valves 58, 64, I0 and It, as hereinbefore described, to openthe valve 58 and admit the pressure fluid to the cylinder 54 to open thevalve 6G to admit I the pressure fluid to the cylinder 53 to close thevalve ill to prevent fluid flow from the cylinder 56 and to close thevalve It to prevent fluid flow from the cylinder 54. With the pressurefluid thus'made to act upon the pistons I2 and 26, it

will be seen that the piston will retract the plate 46 against thetension of the spring 24, thus removing the retracting bias from thetensioning roller 38 and the fluid pressure will act upon the piston I2to cause the piston to move the tensioning roller 38(to strip tensioningposition. While these relays are operating the end of the strip wil1have progressed from the roll stand it to the roll stand 2i] and thestrip will be in a position to be engaged by the tensioning roller 38andto have tension applied thereto. It is understoodthat any suitabletime delay may be introduced into the electromagnetic operating systemfor: the valves or-the relay it may be time delayed so as to permitengagement of the strip I6 by the rolls of roll stand 2i] slightlybefore the tensioning roller reaches the full tensioning position.

When the following end of the strip I6 ha passed through the rolls ofroll stand i8, it will be seen that theenergization of relay 38 will bequickly decreased due to the drop in the load on the drive motor 94 forthe rolls of roll stand I8 and the contact element Hit of relay 3E! willmove to open circuit position causing the deenergiaation of the valves58, Ed, in and I6. The closure of valve 53 will prevent further flow ofpressure fluidto the cylinder 54 and the closure of valve liil'willprevent further flow of pressure fluid to the; cylinder 58. Theopeningof the valve 'lfi will permit flow ofpressure-fluid from" thecylinder 54 to the atmosphere and the opening of-the valve III willpermit the flow of pressure fluidfrom the cylinder 50 toatmosphere; Withthe release of the pressure fluidf'rom the cylinder 54; theoperating'force will be relieved from' the tensioning roller 38 and with threlease of the fluidp'res sure from the cy1inder50 the-retracting forcewillbe released-from the spring and the spring 24- will force the plate46 against th roller on the arm4 2 to move' the terisioning roller tothe inoperative retracted position shown-in the drawings;

It nowthe characteristics of the-stripmaterial or the dimensions ofthe'strip tobe-rolled' are suchas to require-a higher tension than canbe provided by the piston I-2 the piston I4' maybe placed into operationby manually actuating the selector switch 96 to cause the contactelement I02 to engagethe contact elements Ifiiba-nd I03; When theleading end ofthe strip I6 engages the rollsof roll stand I8 therelay3ll-wi1l be actuated to close the circuit hereinbefore-described. tooperate thevalves 78; 84, I0 and 90-; thus operating the piston; 26 toremove the retracting bias of the spring-'24 and operating the piston I4to apply tension to. the" strip I6 in a manner similar to the operationhereinbeiore described in connection with the operation of piston I2.

It will be seen that-while the valvesystem for the piston I2 is actuatedtocause-this pistonto operate the tensioning device, the valves18- and85 will be closed to prevent fluid flow into the e cylinder 55associated with piston l' 'g'and, likewise; when the valve systeniforpiston M'is operated, the valves 58 and $4 will-be closed to preventpressure fluidflow into the-cylinder 5'4'associated with piston I2.

In Fig. 2 IL have shown an. operating system for the tensioning device-Ifl whereina single operating piston is connected to actuatethetensioning roller 38, like reference characters in this and the otherfigures of the drawings designating like parts; In this system aselector switch such as the switch 96 described in connectionwith theapparatus of Fig. I is not required, and a release valve is also not re7 quired. The valve apparatus comprises arelay control valve I8connected to the pressure regulating reservoir by conduitBil andto thecylinder 58- by conduit 82. A conduit 86 connects the cylinder 50- withthe'cy-linder 56 and the release valve ID- is connected by: a conduit1?; to the cylinder 58. The operating windings of the two control valvesIll and 18 are connected in a circuit: which extends from conductorXthrough conductors I04 and I06; the contact element IE8, the conductorI I0, theoperating winding ofv valve "I9, a conductor I32, the operatingwinding of valve I8 and the conductor I34 to conductor'Y. The desiredpressure may be established in the regulated pressure reservoir ashereinbeiore described in connection with the system of Fig. l, and whenthe relay 30 is energized'the valves '59 and I8 will be actuated,..thevalve I8 thenpermitting pressure fluid toiflow into the=cylinders 56 and50 and the valve- In preventing pressure fluid fromflowing out of thecylinder 59'.-

By this pressurefluid actuation of the-piston 28; the biasing spring 24will be retracted and the tensioning roller 38 will-be-moved-bypiston I4from the retracted inoperative position-shown in the figure tostriptensioning positiont, when the energization of the relayslim-decreased the valves10 and I8 will be deenergized by the movementof the contact element I08 of relay 30 to open circuit position. Thevalve I8 will then close to prevent further flow of pressure fluid tothe cylinder 56 and the valve I will open to permit flow of the pressurefluid from the cylinders 56 and 50 to the atmosphere. The actuatingforce will thus be removed from the tensioning device I0 and theretracting force will beremoved from the spring 24 permitting the springto move the tensioning device I0 to the inoperative position shown inthe drawings.

In Fig. 3 there is shown another embodiment of the invention in whichthe operating fluid pressure is maintained constantly upon the operatingpiston I4 and control valves 84 and I0 are provided for controlling thebiasing spring 24. In this embodiment of the invention, since there is aconstant operating force applied to the tensioning device by the pistonI4, the retracting spring 24' must be strong enough to counteract theforce applied by the piston I4 and to move the tensioning device to theinoperative retracted position against the operating force applied bythe piston l4. In order to provide for the retraction of the biasingspring 24, it is necessary to utilize a piston 26 which is larger thanthe piston 26 described in connection with the devices of Figs. 1 and 2.

The elements of the system comprise the piston I4 operating in thecylinder 56 which is connected to the regulated pressure reservoir bythe conduit 80 and to a control valve 84 by a conduit 86. A conduit 88connects the cylinder 50 with the control valve 84 and the cylinder 50'is connected by a conduit I2 to a release valve I0. A control circuit isprovided for the valves and extends from the conductor X throughconduotors I04 and I06, contact element I08, conductor IIO, theoperating winding of valve I0, conductor I38, the operating winding ofvalve 84 and the conductor I40 to the conductor Y.

, In the operation of this system when the energization of relay 30 isincreased as hereinbefore described, the valve 84 will be opened and thevalve I0 will be closed. The opening of vave 84 will permit the flow ofpressure fluid to the cylinder 50' and the closure of the valve III willprevent the flow of pressure fluid from the cylinder 50'. Theapplication of fluid pressure to the piston 26' in the cylinder 50' willcause the piston 26' to retract the spring 24, thus relieving theretracting bias from the bell crank 32 and permitting the force which isconstantly acting upon the bell crank through the piston I4 to move thetensioningv device to stripv tensioning position. Upon movement of thecontact element I08 to open circuit position, the valve 84 will bedeenergized and closed, thus preventing further flow of pressure fluidto the cylinder 50' and the valve I0 will be deenergized and opened topermit the flow of pressure fluid from the cylinder 50' to theatmosphere. With the release of fluid pressure from the piston 26', thespring 24 will be allowed to move the bell crank 32 in thecounterclockwise direction against the force applied by the piston I4 tomove the tensioning roller to inoperative retracted position.

If it is desired to subject the strip to a higher tension than can beprovided by the piston I4 alone, the embodiment of the invention shownin Fig. 4 may be employed. In Fig. 4 there is shown the pistons I2 andI4 connected in parallel arrangement in the pressure fluid system to beactuated. simultaneously by a control system such as is shown in Fig. 2.By reference to this figure, it will be seen that a conduit I36 isconnected to conduct pressure fluid to the cylinder 54 through a conduit62 and to the cylinder 56 through a conduit 82 simultaneously and thatboth cylinders 54 and 56 are connected to the conduit 66 which is alsoconnected to the cylinder 50. The operation of this system is the sameas that described in connection with the system of Fig. 2 with the twopistons I2 and I4 acting simultaneously to provide a strip tension ofthe order of the sum of the tensions that could be provided by thepistons I2 and I4 acting singly.

In Fig. 5, I have shown a tensioning control system operatedsubstantially the same as the system shown in Fig. 3 with the exceptionthat both of the pistons I2 and I4 are operated simultaneously, asdescribed in connection with the system shown in Fig. 4. In this systemit will be seen that a spring 24 is provided, the spring having enoughstrength to counteract the constant force applied by both pistons I2 andI4 to the tensioning device to hold the tensioning device in theinoperative retracted position. In this system also a larger piston 26"and cylinder 50" are provided to supply the necessary retracting forcefor the larger biasing spring 24". It will be seen that the cylinders 54and 56 are both connected by the conduit to the regulated pressurereservoir and both are also connected to the control valve 84. In allrespects the operation of this system is substantially the same as theoperation of the system described in detail in connection with theshowing of Fig. 3.

In case it is desirable that three ranges of tension be provided, thesystem shown in Fig. 6 may be used. This control system is operative toselectively actuate the tensioning device by either piston I2 or pistonI4 or both pistons I2 and I4. The elements of this system are the sameas those shown and described in connection with the device of Fig. 1with the exception of the control circuits for the several valves. Inthe device of Fig. 6, a selector switch I42 is provided having fixedcontact elements I44, I46 and I48 corre sponding to the contact elements98, I00, and I03 of the system of Fig. 1. Movable contact elements I50and I52 are provided and contact element I50 is so shaped that when itis moved one step in the left-hand direction, the control circuits forthe valves which control piston I2 will be energized and when it ismoved two steps in the left-hand direction, the control valves for bothof the pistons I2 and I4 will be energized. In a like manner when thecontact element I52 is moved one step in the right-hand direction, thecontrol valves for the piston I4 will be energized and when it is movedtwo steps in the right-hand direction, the control valves for both ofthe pistons I4 and I2 will be energized.

The control circuits for the selection of the operation of either pistonI2 or I4 by the movement of the selector switch I42 one step in the leftor right-hand directions are the same as those described in detail inconnection with the system of Fig. 1 with the movable contact elementsI50 and I52 substituted for the movable contact elements 91 and I02 ofthe device of the system of Fig. 1, and the fixed contact elements I44,I46 and I48 substituted for the fixed contact elements 96; I00 and I03of the system of Fig. 1. In the second step position of either contactelement I50 or I52, it will be seen that the movable contact elementswill engage all three of the contactelements I44, I46 and I48, and. thusthe operating "circuits of both sets .of control "valves will beenergized when the relay .36 moves its acontact elemeritiflsS toclosed-circuit position.

Thus in the operation :of the rsystemof 6 Kit is :desiredto provide'alow :range of tension on the'strip, the selectonswitch 'I'42Jmay'bemanually actuated to move the 'contact lelement I50 one step intoengagement with the montact aelements "I44and I461to thusactuatethecontrol valves for the piston I2. If an intermediate range oftensions is desired, the selector'switch I'42rmay bemanuallyzactuated'to move 'the movable contact element .152 one step.into engagement with the contact elements 146 .and 148, thus actuatingthe control valves for the piston "I 4. If itis desired that ;a :stillhigher range of tension be :applied :to the strip, :the selector switch-'I42 may be manuallyactuated :to move its movable contact elements I50and IE2 two'steps-in'eitherthe zright or left-hand directions to selectfor .energization the control valves'for both *of the pistons '12 and I4.

In *Fig. 7, I :haveshown a control system for pistons TI-2 and M in'which'eitherof thepistons may be actuated in a manner similar to that525 showninFig. 3. In this system the control valves 58 and and therelease valve 16 are :provided TOIlthEECOI-IIZI'DI'OJ. :pressure fluidflow toand from the cylinder *54 and the release valve 10 is providedv:for the "control of pressure fluid flow "from the cylinder '50, Inalike manner control valves .H3 and 84 and release valve 90 are :pIOVidd=for controlling the operation of :piston I4. In this system the spring24' must be of sufiicient strength :to-overcome-th'e force applied tothebell crank "by thepiston IA-under the action of the pressure fluid"similar to that :shown in Fig. 3. A selectorswitch 454 is providedhaving movable contact elements 45.6 and H58 which, when movedinitheleft-hand direction; will establish a connection betweenfixedcontactelements I60 and I62 and 1.64 and I56, respectively.Movablecontact elements 68 :and I I are also provided and these contactelements when moved in the right-hand direction will establishconnection between the contact elements I62 "and I12 and I66 and I16,respectively.

When the SGIGCtOIrSWiIJCh I54 is actuatedin the left-hand direction, thecontrol valve58 andthe release valve 16 will be energized through acircuit which extends from theconductor X through the conductor I85, thecontact element I56, the conductor 105, the operating'winding-of valve=16, conductor I88, the operating winding of valve 58 and conductor "I82to the conductor Y. This energizationiof valves58 and Hi will causevalve 58 to open to admit pressure fluid to the cylinder 54 from theregulated pressure reservoir and will .close valve 16 to prevent therelease of pressure fluid from the cylinder 54. In this condition of theapparatus, the piston 12 will be applying its (force to the tensioningdevice tending to move the tensioning deviceto opera- ,tive "position.but this force will be counteracted by .the biasing spring 24' and thetensioning device will remain .in the retracted inoperative position.

The actuation of the selector switch I54 in theleft-hand :direction willselect vfor operation the control \valve 64 and the release valve 10, sothat when the contact element I08 :of the relay 3.0 is moved to closedcircuit position, a circuit will be completed for the valves 64 and '10extending from the contact element X to the conductors I64 and .I 06,.contactelement .l 08,

conductor III], the operating winding of the valve 10, conductor 1 I2,contact element I56, the conductor I16, the operating winding of valve64, theconductors 118, I and I82 to the conxductor Y. This actuation ofthe valves 64 and 10 will permit the flow of pressure fluid to thecylinder 50 through the conduit 68 and will prevent the flow'of pressurefluid from the cylinder 50 through the conduit I2, thus sub- .iecti'ngthe piston 26 to fiuidpressure to retract the spring 24' and permit thepiston I2 to move the tensioning device to operative position.

In .a :like manner when the selector switch I54 is actuated in theright-hand direction, a circuit will be closed to energize the control'valve I8 and the release valve 90, the circuit extending from theconductor IX through the conductor I05, contactelement I10, theconductor 190, the operating winding of valve 90, the contductor I92,the operating winding of valve 78 and conductors I94 and H32 to theconductor At the same time the control valve 84 and the release valve'10 will be selected for operation by the engagement of contact elementI68, with contact elements I 62 and I12 through a circuit extending fromconductor X through conductors I04 and I66, contact element I08, when itis'in closed circuit position, conductor N0, the

operating winding of valve 10, conductor H2,

contactelement 168,-conductor -I 84, the operating winding of valve '84and theconductors I80 and ISZto-the conductor Y. Thus the valves 18 andwill be selectively operated by the actuation of the selector switch 154in the right-hand direction to apply operative force to the tension-:ing devicethroughthe piston I4 and then when the relay 30 moves itscontact I08 to its closed "circuit position, the valves 10 and 84 willbe operated to cause the piston'26 to retract the spring 24' and permitthe tensioning device to be operated by the piston I4. Thus it will beseen that the control system of Fig. '7 will selectively actuate thetensioning device by either piston 12 to provide a low range of tensionsor by the piston I4 to provide a higher range of "tensions.

If a 'low range of tensions, an intermediate range of "tensions and ahigh range of tensions are desired, the control system of Fig. 8 may beemployed. This system will so control the actuation ofthetensioning-device-as to provide a range-of tensions with piston *IZacting alone, piston I4 actingalone or pistons 12 and I4 actingtogether. This system is very :similar to that shown in Fig. *7, exceptthat a selector switch similar to-the-selector switch'shown in thesystem of Fig. -6 is'provided. In this system the biasing spring 24"must be made strong enough to counteract the forces applied to thetensioning device by both pistons I2 and I4 and the piston 26 'must beof sufficient size to counteract the biasing spring 24" as was explainedin connection with the system of Fig. 5.

In the system of Fig. 8,a selector switch I96 is provided. havingmovable contact elements 200 and 202 which when moved-one step in theleft-hand direction will engage contact elements .204 and 205 and 208and 210, respectively, and when moved two steps inthe-left-handdirection will engage contact elements :204, 206 and 2I6 and contactelements 208, 210 and 2I8, respectively. The selector switch I86 alsoincludes movable contact elements -2I2 and 244 which when the selectorswitch -.is moved one step in the right-hand direction will engagecontactelements 2fl4and 2I6 and contact elements 208 and 2I8,respectively, and when moved two steps in the right-hand direction willengage contact elements 204, 206 and 2I6 and 208, 2I0 and 2I8,respectively. Thus the first step in the movement of the selector switchI96 in the left-hand direction will actuate the control valve 53 and therelease valve "I6 for the piston I2 through a of valve III, conductorII2, contact element 200,

conductor 220, the operating winding of valve 64, and conductors 224,226 and 228 to the conductor Y.

'In' a like manner, when the selector switch I 95 is moved one step inthe right-hand direction, a circuit extending from conductor X throughthe conductor 232, contact element 2I4, conductor -238, the operatingwinding of'the valve 90, conductor 24!), the operating winding of valve18, and conductors 244 and 228 to the conductor Y will be energized toactuate the valves I8 and 90. At the same time a circuit will beselected for actuating the valves 84 and I when the relay 30 moves itscontact element I08 to closed circuit position through a circuit whichextends from iconducto'r'X through conductors IM and I06,

contact element I08, conductor III], the operating winding of valve In,conductor II2, contact element; 2I2, the conductor 230, the operatingwinding of valve 84 and the conductors 226 and 228 to the conductor Y.If now it is desired to actuate the tensioning device by both pistons I2and I4, the selector switch I96 may be moved in either direction twosteps to energize the selector circuits for the control valves 58 and 18and the release valves 16 and 90 simultaneously and to set up thecontrol circuits for the control valves 64, 84 and III as hereinbeforedescribed.

It will be seen that I have provided control systems for a fluidpressure operated strip tensioning device which will function to subjecta strip of material to any desired range of tensions which willautomatically hold the tensioning device in retracted inoperativeposition while the strip is not in a position to be tensioned by thedevice, and which, when the strip moves to a position tobe tensioned bythe device, will automatically operate to apply the desired tension tothe strip.

'In' compliance with the requirements of the patent statutes I haveshown and 7 described herein the preferred embodiments of my invention.It is to be understood, however, that the invention is notlimited tothe'precise constructions shown and described but is capable ofmodification by one skilled in the art, the embodiments herein shownbeing merely illustrative of the principles of my invention.

I claim as my'invention:

,1. In a control system for a strip tensioning device having an idlingroller disposed to bear against the strip when actuated to deflect itfrom its normal pass line as it passes between two work devices to thussubject the strip to tension,

means for biasing the roller for movement away from strip tensioningposition, counteracting means for rendering said biasing meansinoperative to act upon the roller, means for actuating the roller tostrip tensioning position and control means for selectively renderingsaid counteracting means efiective or inefie'ctive.

2. In a control system for a strip tensioning device having an idlingroller disposed to bear against the strip when actuated to deflect itfrom its normal pass line as it passes between two work devices to thussubject the strip to tension, means for biasing the roller for movementaway from strip tensioning position, counteracting means for renderingsaid biasing means inoperative to act upon the roller, means foractuating the roller to strip tensioning position, and control means foractuating said counteracting means and said roller actuating means.

3. In a control system for a strip tensioning device having an idlingroller disposed to bear against the strip when moved to strip tensioningposition to deflect it from its normal pass line as it passes betweentwo work devices to thus tension the strip, a first means biasing theroller for movement toward strip tensioning position, a second means forbiasing the roller for movement away from strip tensioning position,said second biasing means having sutficient force to move the rolleraway from strip tensioning position against the force of said firstbiasing means, and counteracting means for rendering said second biasingmeans inoperative to act upon the roller.

4. In a system for subjecting a strip of material to tension as itpasses between two adjacent work devices, an idling roller disposed tobemade to bear against the strip and thus subject the strip to tension bydeflecting it from its normal pass line between the work devices, meansfor biasing the idling roller for movement away from strip tensioningposition, counteracting means for rendering said biasing meansinoperative to act upon the roller, means for moving said roller tostrip tensioning position, and means responsive to the positioning ofthe leading end of the strip as it passes through said work devices foractuating said counteracting means and said means for moving said rollerto strip tensioning position.

5. In a system for subjecting a strip of material to tension while itpasses between two adjacent work devices, an idling roller disposed tobe actuated into engagement with the strip and thus subject the strip totension by deflecting it from its normal pass line between the workdevices, means for biasing the idling roller for movement away fromstrip tensioning position, counteracting means for rendering saidbiasing means inoperative to act upon the roller, means for moving saidroller to strip tensioning position, and means responsive to theposition of the strip with respect to said work devices for so actuatingsaid counteracting means and said means for moving said roller to striptensioning position as to subject the strip to tension during the timeit extends between and is engaged by the work devices.

6. In a system for subjecting a strip of material to tension while itpasses between two adjacent work devices, an idling roller disposed tobe actuated into engagement with the strip and thus subject the strip totension by deflecting it from itsnormal pass line between the workdevices, means for biasing the roller for movement away from striptensioning position, a firstoperating means for causing the roller toengage .and apply a predetermined force to the strip, a second operatingmeans .for causing the roller to engage :and apply a predetermined forceto the strip, counteracting :means for rendering said biasing meansimperative to :act upon .the roller, and means for'sele'ctive1yactuatingsaid first and second operating means and for actuating saidcounteracting means.

7. In a system for subjecting a strip of materialto tension'while itpasses between two adjacent workdevices, an idling roller disposed to beactuated into engagement with the strip and thus .subject the strip totension by deflecting it from its normal .pass line between the workdevices, means for biasing the roller for movement-away from striptensioning positioma first operating means for causing the roller toengage and apply a predetermined force to the strip, a second -operatingmeans for causing the roller to engage :and apply a predetermined forceto the strip, counteracting means for renderingsaid biasing meansinoperative to act upon the roller, and means for selectively actuatingeither 'orboth of said first and second operating means and i'oractuating said counteracting means.

8. In a control system for a strip tensioning device having an idlingroller adapted to be actuated into engagement with the strip to deflectit from its normal pass line as it passes between two work devices tothus subject the strip to tens'ion, a first operating means for causingthe roller to engage and apply a predetermined force to the strip, asecond operating means for causing the roller to engage and-apply apredetermined force to "the'strip, means biasing the roller for movementaway from strip tensioning positiomsaid biasing means having surficientforce to move the 'roller away from strip tensioning position againstthe force of either said firstor said second operating means, means forcounteracting said biasing means, means for selectively actuating saidfirst and second operating 'means, and means for actuating saidcounteracting means.

9. In a control system for a strip tensioning device having an idlingroller adapted to be actuated into engagement with the strip to deflectit "from its *normal pass line as it passes between two work devices tothus subject the strip to tension, a first operating means for causingthe roller to engage and apply a predetermined force to the strip, asecond operating means for causing the roller to engage and apply apredetermined force to the strip, means biasing the roller for movementaway from striptensioning position, said biasing means having sufficientforce to move the roller away from strip tensioning position against theforce of both said first and said second operating means combined, meansI for counteracting said biasing means, means for selectively actuatingeither or both of said operating means, and means for actuating saidcounteracting means.

10. In a system for subjecting a strip of material to tension while itpasses between two adjacent work devices, an idling roller disposed tobe actuated into engagement with the strip and thus subject the strip totension by deflecting it from its normal pass line between the workdevices, means biasing said roller away from strip tensioning position,pressure fluid operated means for counteracting said biasing means toremove its bias from said roller, pressure fluid operated means foractuating said roller to strip tensioning position, inlet valve meansfor admitting pressure fluid to both of said pressure fluid operatedmeans, outlet valve means for permitting pressure fluid to fiowirom bothof said'pressure fluid operatedmeans, means forsimultaneouslyopeningsaid inlet valve'means and closing said outletvalve means, and means for simultaneously closing said inlet valve meansand opening said outlet valve means.

11. In a system for subjecting a strip of .material to tension while itpasses between two adjacent work devices, an idling roller disposed tobe actuated into engagement with the strip and thus subject the strip totension by deflecting it from its normal pass line between the .workdevices, means biasing said roller away from strip tensioning position;pressure fluid operated means for counteracting said biasing means toremove its bias .from said roller, pressure fluid operated means foractuating said roller tostrip tensioning position, means for maintainingfluid pressure on said pressure fluid operated roller actuating means,said roller biasing means having sufficient force to hold said rolleraway from strip tensioning position against the force of said rolleractuating means, inlet valve "means for admitting pressure fluid to saidpressure fluid operated counteracting means, outlet valve means forpermitting pressure fluid to flow from said counteracting means, meansfor simultaneously opening said inlet valve means and closing saidoutlet valve means, and means for simultaneously closing said inletvalve means and opening said outlet valve means.

12. In a system for subjecting a strip of material to tension while itpasses between twoadjacent work devices, an idling roller disposed to beactuated into engagement with the strip and thus subject the strip totension by deflecting it from its normal pass line between the workdevices, meansbiasing said roller away from strip tensioningposition,-pres-sure fluid operated means for counteracting said biasingmeans to remove its bias from said roller, pressure fluid operated meansfor actuating said roller to strip tensioning position, inlet valvemeans for admitting pressure fluid to'both of said pressure fluidoperated means, outlet valve means for permitting pressure fluid to flowfrom both of said pressure fluid operated means, means forsimultaneously opening said inlet valve means and closing said outletvalve means, and means for simultaneously closing said inlet valve meansand opening said outlet valve means, said means for actuating saidroller comprising a plurality of pressure fluid operated pistons.

1.3. In a system for subjecting a strip of material to tension while itpasses between two adjacent work devices, an idling roller disposed tobe actuated into engagement with the strip and thus subject the strip totension by deflect ing it from its normal pass line between the workdevices, means biasing said roller away from strip tensioning position,pressure fluid operated means for counteracting said biasing means toremove its bias from said roller, pressure fluid operated means foractuating said roller to strip tensioning position, means formaintaining fluid pressure on said pressure fluid operated rolleractuating means, said roller biasing means having suflicient force tohold said roller away from strip tensioning position against the forceof said roller actuating means, inlet valve means for admitting pressurefluid to said pressure fluid operated counteracting means, outlet valvemeans for permitting pressure fluid to flow from said counteractingmeans, means for simultaneously opening said inlet valve means andclosing said outlet valve means, and means for simultaneously closingsaid inlet valve means and opening said outlet valve means, said meansfor actuating said roller comprising a plurality of pressure fluidoperated pistons.

14. In a system for subjecting a strip of material to tension while itpasses between two adjacent Work devices, an idling roller disposed tobe actuated into engagement with the strip and thus subject the strip totension by deflecting it from its normal pass line between the workdevices, means biasing said roller away from strip tensioning position,pressure fluid operated means for counteracting said biasing means toremove its bias from said roller, pressure fluid operated means foractuating said roller to strip tensioning position, said means foractuating said roller to strip tensioning position comprising aplurality of pressure fluid operated pistons, an inlet valve for each ofsaid pistons for admitting pressure fluid to said pistons, an outletvalve for each of said pistons for permitting pressure fluid flow fromsaid pistons, a control valve connected in a fluid conduit between eachof said pistons and a common conduit connected to said counteractingmeans, an outlet valve for said counteracting means, control means forselectively simultaneously-opening the inlet valve, closing the outletvalve, and opening the control valve for any one of said pistons andclosing the outlet valve for said counteracting means and forsimultaneously actuatingsaid selectively operated valves to thepositions opposite to their selectively actuated positions 15. In asystem forsubjecting a strip of material to tension while it passesbetween two adjacent work devices, an idling roller disposed to be madeto bear against the strip and thus subject the strip to tension bydeflecting it from its normal passline between the work devices, meansbiasing said roller away-from strip tensioning position, pressure fluidoperated means for counteracting said biasing means to remove its biasfrom said roller, pressure fluid operated means for actuating saidroller to strip tensioning position, said means for actuating saidroller to strip tensioning position comprising a plurality of pressurefluid operated pistons, an inlet valve for each of said pistons foradmitting pressure fluid to said pistons, an outlet valve for each ofsaid pistons for permitting pressure fluid flow from said pistons, acontrol valve connected in a fluid conduit between each of said pistonsand a common conduit connected to said counteracting means, an outletvalve for said counteracting means, control means for selectivelysimultaneously opening the inle't'valve, closing the outlet valve, andopening the control valve for any one or all of said pistons and closingthe outlet valve for said counteracting means-and for simultane- "ouslyactuating said selectively operated'valves to the positions opposite totheir selectively actuated positions.

16. In a system for subjecting a strip of material to tension while itpasses between two adjacent work devices, an idling roller disposed tobe made to bear against the strip and thus subject the strip to tensionby deflecting it from its normal pass line between the work devices,means biasing said roller away from strip tensioning position, pressurefluid operated means for counteracting said biasing means to remove itsbias from said roller, pressure fluid operated means for actuating saidroller to strip tensioning position, said means for actuating saidroller comprising a plurality of pressure fluid operated pistons, saidroller biasing means having suflicient force to hold the roller awayfrom strip tensioning position against the force of all of saidplurality of pistons, an inlet valve for each of said pistons foradmitting pressure fluid to said pistons, an outlet valve for each ofsaid pistons for permitting pressure fluid flow from the pistons, acontrol valve connected in a fluid conduit between each of the pistonsand a common conduit connected to said counteracting means, an outletvalve for said counteracting means, control means for selectivelysimultaneously opening the inlet valve, and closing the outlet valve forany one-or all of said pistons; control means for thereaftersimultaneously opening the control valve of the piston or pistons whoseinlet and outlet valves have been selectively operated and closingsaid-counteracting means outlet valve.

GERHARD P. LESSMANN.

